Control of insect pests through mating disruption is performed by releasing a synthetic pheromone of a target insect pest into the air, disturbing mating communication between male and female insect pests to reduce their mating ratio, and controlling the birth of the next generation. A preparation for releasing this synthetic pheromone is required to have a performance of stably releasing the sex pheromone during an emergence period (for from 2 to 6 months) of the insect pest.
In a sustained release preparation already used in practice, a sex pheromone is enclosed in a polymer tube or a polymer ampoule, and released by diffusion and transmittance through the wall of the tube or ampoule to the air. Examples of the polymer tube include a tube comprising a metal wire along the tube (PTL1 and PTL2), a tube bent into a ring (PTL3), and a folded tube (PTL4). In PTL5, there is proposed an annular sustained release preparation 110 having the ends of two polymer tubes 112 and 113 welded into a ring as shown in FIG. 12. It is hung on or winded around the branch or trunk of a plant upon use.